You asked
I would like to know how much the UK's illicit drug market was reported to be worth last year.
We said
Thank you for your enquiry.
Unfortunately, we do not hold the information you have requested.
Whilst we are unable to help you with your request, we do hold some data on drug-related crime which may be of interest to you. In Appendix Table A4, published alongside our latest quarterly bulletin ‘Crime in England and Wales, year ending December 2018’, we publish data on the number of police recorded crimes for drug possession and trafficking. These data are available for England and Wales (see Appendix table A4) as well as at Police Force Area level and Community Safety Partnership Area level (which equates in the majority of instances to local authorities).
You can access the appendix tables here: https://www.ons.gov.uk/peoplepopulationandcommunity/crimeandjustice/datasets/crimeinenglandandwalesappendixtables
The source referred to above only cover England and Wales; we do not hold police recorded crime data covering the whole of the UK.
Crime-related data for Scotland are published by the Scottish Government and are available here: https://www.gov.scot/Topics/Statistics/Browse/Crime-Justice
Police recorded crime data for Northern Ireland are published by the Police Service of Northern Ireland and are available here https://www.psni.police.uk/inside-psni/Statistics/. Data from the Northern Ireland Crime Survey are published by the Department of Justice and are available here: https://www.justice-ni.gov.uk/articles/northern-ireland-crime-survey.
You may also be interested to know that the main source of data on drugs prices is in the UK’s Annual Focal Point report on drugs, although this is all at a national rather than local authority level: https://www.gov.uk/government/publications/united-kingdom-drug-situation-focal-point-annual-report